FBC, Fluid and Electrolyte Disturbances Flashcards
Iron (ferrous sulfate, ferrous fumarate) is indicated for:
- IDA rx
- prophylaxis of IDA (e.g. at risk sue to poor diet, malabsorption, mennorhagia, haemodialysis..)
Iron is absorbed best in its ferrous state (fe…) in the ___ and ___, its absorption is increased by ____ ___ and dietary acids e.g. ascorbic acid (vit c)
Once absorbed in blood is is bound by ____ which transports it either to be used in the ___ for ______ or to be stored as ____ in the ___, reticuloendothelial system, BM, spleen or skeletal muscle
- Fe2+ in duodenum and jejunum
- increased by stomach acid
- bound by transferrin
- used in bone marrow for erythropoesis or stored in liver as ferritin
Iron therapy can exacerbate bowel symptoms in pts with intestinal disease e.g. ___ ___ ____…
Use IV therapy in caution in pts with an ___ predisposition - due to risk of an anaphylactic reaction
- e.g. IBD, diverticulitis, intestinal strictures
- an atopic predisposition
NB: oral iron can turn pts stool black and sticky
Oral iron salts can reduce the absorption of other drugs including _____ and ______(so take few hours apart)
- levothyroxine
- bisphosphonates
Vitamins
- Thiamine (b1) is used in rx/prevention of:
- folic acid (b9) is used in rx of _______ anaemia due to deficiency and in __ ____ to reduce risk of ___ defects
- hydroxycobalamin (b12) is used in rx of “” anaemia and ___ ____ ____ of the cord as result of deficiency
- Phytomenadione (vit K) is given to all newborns to prevent vit-K deficiency ___ and given to reverse the ___ effect of ___ (+/- ___ complex ___)
- b1: Wernicke’s and Korsakoff’s psychosis
- b9: Megaloblastic anaemia and 1st trimester to reduce neural tube defects risk
- b12: Megaloblastic anaemia and subacute combined degeneration of the cord
- vit K: prevent vit-K def. bleeding and to reverse the anticoag. effect of warfarin +/- prothrombin complex concentrate
In a pt with folate and B12 deficiency, what is the risk if you replace the folate first without correcting B12 deficiency?
- can hasten progression of neurological manifestations of B12 deficiency
- major risk is of provoking subacute combined degeneration of the cord
Pabrinex is a compound preparation of __ and __ vitamins, given by ___ as prophylaxis for patients at high risk of ____ deficiency. Dose is given 12-hrly for __ days.
- Pabrinex: B and C vitamins, given by IV injections, -high risk of thiamine deficiency
- 12-hrly for 3 days
To prevent NT defects, pre-conception what dose of folic acid is recommended until week 12.
If at higher risk (e.g. epilepsy), what dose is used?
- 400micrograms
- 5mg
Give an example of colloids (plasma substitutes) and 1 indication for their administration:
- gelatins, albumin
- used to expand circulating volume in states of impaired tissue perfusion (but NaCl is usually preferred)
- albumin is used in cirrhotic liver disease to prevent effective hypovolaemia in large-volume paracentesis (when draining ascitic fluid)
IV colloids e.g. gelatin, albumin contain comparatively ___, _______ active ____ in ____.
These in principle ____ readily ____ a _______ membrane and their osmotic effect ‘holds’ the infused volume in the intravascular space, (which would make them more effective at expanding circulating volume than crystalloids that do cross a membrane) why is this not usually true?
- large, osmotically active molecules in suspension
- cannot readily cross a semipermeable membrane
- those requiring volume expansion (e.g. for sepsis) have ‘leaky’ capillaries so fluid is more rapidly lost into interstitium
Gelatin colloids can cause hypersensitivity and anaphylactic reactions. Colloids also contain __ so an adverse effect is when this diffuses into the interstitium, it promotes ____. Excessive plasma volume expansion can do what to the heart –> what adverse effect?
- Na+
- oedema
- increase LV filling beyond point of maximum contractility causing fall in CO and pulmonary oedema
What 2 conditions should you exercise caution in prescribing colloids?
-heart failure
-renal impairment
to avoid volume overload
Colloid prescriptions:
- for shock, Gelofusine ____mL to be given over __minutes
- for large-vol paracentesis: ___mL albumin __% solution for every __L ascitic fluid drained
- 250mL over 5 mins
- 100mL albumin 20% solution for every 2L fluid drained
Hartmann’s is compound sodium lactate. Given for maintenance or for resus during shock. What type of solution is it? It has one adv over 0.9% saline relating to electrolytes, what is this?
Crystalloid
-it has a lower chloride content so less likely to cause hyperchloremic acidosis
Compound sodium lactate (hartmann’s) is best avoided in severe liver disease because there may not be sufficient capacity to ?
-to metabolise lactate
With 0.9% saline you can use different concentration of K+ e.g. 5mmol/L, 20mmol/L, 40 mmol/L. How does this differ to Hartmann’s?
-less flexible. Hartmann’s K+ content is fixed at 5mmol/L
Sodium Chloride (0.9% or 0.45%) are used for maintenance, for shock resus, and one extra indication? NB: glucose/sterile water could also be used for this purpose
-for reconstitution and dilution of drugs needed for injection/infusion
The conc of chloride in 0.9% saline is 154mmol/L, how does this compare to the conc o chloride in the ECF and therefore what risk is associated with it’s use? Explain this
- ECF is lower (100mmol/L) so risk of hyperchloraemia –> acidaemia
- as Cl- conc rises, bicarbonate (HCO3-) conc falls to maintain electroneutrality
- less bicarbonate -> pH rises as more K+ and H+ about
In severe CKD what effect does impaired phosphate excretion and reduced activation of vitamin D have on calcium levels?
What gland dysfunction does this stimulate? Leading to dystrophy of what?
- hypocalcaemia (and hyperphosphataemia)
- secondary hyperparathyroidism
- leads to dystrophy of bones aka renal osteodystrophy
Oral calcium can cause SE in what system, e.g. ?
IV calcium gluconate for high K+ treatment has the adverse effect of what if given too fast?
- oral => GIT effects e.g. dyspepsia, constipation
- IV => risk of cardiovascular collapse
thinking about the effect vitamin D has on a certain electrolyte. In what situation would administration of vitamin D be contraindicatied?
Hypercalcaemia
Oral calcium reduces the absorption of many drugs, suggest 2?
- iron
- bisphosphonates
- tetracyclines
- levothyroxine
IV calcium must not be allowed to mis with sodium bicarbonate due to risk of what?
-risk of precipitation
What is the dose, route and time of calcium gluconate given in sever hyperkalaemia with ECG changes:
-10mL of 10% IV calcium gluconate over 10 minutes
